BLOGS

An Anthrobot is shown, depth colored, with a corona of cilia that provides locomotion for the bot. Credit: Gizem Gumuskaya, Tufts University

Topics: Applied Physics, Biology, Biomimetics, Biotechnology, Research, Robotics

Researchers at Tufts University and Harvard University's Wyss Institute have created tiny biological robots that they call Anthrobots from human tracheal cells that can move across a surface and have been found to encourage the growth of neurons across a region of damage in a lab dish.

The multicellular robots, ranging in size from the width of a human hair to the point of a sharpened pencil, were made to self-assemble and shown to have a remarkable healing effect on other cells. The discovery is a starting point for the researchers' vision to use patient-derived biobots as new therapeutic tools for regeneration, healing, and treatment of disease.

The work follows from earlier research in the laboratories of Michael Levin, Vannevar Bush, Professor of Biology at Tufts University School of Arts & Sciences, and Josh Bongard at the University of Vermont, in which they created multicellular biological robots from frog embryo cells called Xenobots, capable of navigating passageways, collecting material, recording information, healing themselves from injury, and even replicating for a few cycles on their own.

At the time, researchers did not know if these capabilities were dependent on their being derived from an amphibian embryo or if biobots could be constructed from cells of other species.

In the current study, published in Advanced Science, Levin, along with Ph.D. student Gizem Gumuskaya, discovered that bots can, in fact, be created from adult human cells without any genetic modification, and they are demonstrating some capabilities beyond what was observed with the Xenobots.

The discovery starts to answer a broader question that the lab has posed—what are the rules that govern how cells assemble and work together in the body, and can the cells be taken out of their natural context and recombined into different "body plans" to carry out other functions by design?

Anthrobots: Scientists build tiny biological robots from human tracheal cells, Tufts University

Researchers from the University of Connecticut and colleagues have created a highly durable, lightweight material by structuring DNA and then coating it in glass. The resulting product, characterized by its nanolattice structure, exhibits a unique combination of strength and low density, making it potentially useful in applications like vehicle manufacturing and body armor. (Artist’s concept.)

Topics: Biotechnology, DNA, Material Science, Nanomaterials

Researchers have developed a highly robust material with an extremely low density by constructing a structure using DNA and subsequently coating it in glass.

Materials possessing both strength and lightness have the potential to enhance everything from automobiles to body armor. But usually, the two qualities are mutually exclusive. However, researchers at the University of Connecticut, along with their collaborators, have now crafted an incredibly strong yet lightweight material. Surprisingly, they achieved this using two unexpected building blocks: DNA and glass.

“For the given density, our material is the strongest known,” says Seok-Woo Lee, a materials scientist at UConn. Lee and colleagues from UConn, Columbia University, and Brookhaven National Lab reported the details on July 19 in Cell Reports Physical Science.

Strength is relative. Iron, for example, can take 7 tons of pressure per square centimeter. But it’s also very dense and heavy, weighing 7.8 grams/cubic centimeter. Other metals, such as titanium, are stronger and lighter than iron. And certain alloys combining multiple elements are even stronger. Strong, lightweight materials have allowed for lightweight body armor and better medical devices and made safer, faster cars and airplanes.

Scientists Create New Material Five Times Lighter and Four Times Stronger Than Steel. Sci-Tech Daily

Reference: “High-strength, lightweight nano-architected silica” by Aaron Michelson, Tyler J. Flanagan, Seok-Woo Lee, and Oleg Gang, 27 June 2023, Cell Reports Physical Science.
DOI: 10.1016/j.xcrp.2023.101475

An RNA-making molecule crystallizes on magnetite, which can bias the process toward a single chiral form. S. FURKAN OZTURK

Topics: Biology, Biotechnology, Chemistry, Magnetism, Materials Science

In 1848, French chemist Louis Pasteur discovered that some molecules essential for life exist in mirror-image forms, much like our left and right hands. Today, we know biology chooses just one of these “chiral” forms: DNA, RNA, and their building blocks are all right-handed, whereas amino acids and proteins are all left-handed. Pasteur, who saw hints of this selectivity, or “homochirality,” thought magnetic fields might somehow explain it, but its origin has remained one of biology’s great mysteries. Now, it turns out Pasteur may have been onto something.

In three new papers, researchers suggest magnetic minerals common on early Earth could have caused key biomolecules to accumulate on their surface in just one mirror image form, setting off positive feedback that continued to favor the same form. “It’s a real breakthrough,” says Jack Szostak, an origin of life chemist at the University of Chicago who was not involved with the new work. “Homochirality is essential to get biology started, and this is [a possible]—and I would say very likely—solution.”

Chemical reactions are typically unbiased, yielding equal amounts of right- and left-handed molecules. But life requires selectivity: Only right-handed DNA, for example, has the correct twist to interact properly with other chiral molecules. To get [life], “you’ve got to break the mirror, or you can’t pull it off,” says Gerald Joyce, an origin of life chemist and president of the Salk Institute for Biological Studies.

Over the past century, researchers have proposed various mechanisms for skewing the first biomolecules, including cosmic rays and polarized light. Both can cause an initial bias favoring either right- or left-handed molecules, but they don’t directly explain how this initial bias was amplified to create the large reservoirs of chiral molecules likely needed to make the first cells. An explanation that creates an initial bias is a good start but “not sufficient,” says Dimitar Sasselov, a physicist at Harvard University and a leader of the new work.

‘Breakthrough’ could explain why life molecules are left- or right-handed, Robert F. Service, Science.org.

New research from Chalmers University of Technology, Sweden, and the University of Freiburg, Germany, shows that wounds on cultured skin cells heal three times faster when stimulated with electric current. The project was recently granted more funding so the research can get one step closer to the market and the benefit of patients. Credit: Science Brush, Hassan A. Tahin

Topics: Applied Physics, Biotechnology, Medicine

Chronic wounds are a major health problem for diabetic patients and the elderly—in extreme cases, they can even lead to amputation. Using electric stimulation, researchers in a project at Chalmers University of Technology, Sweden, and the University of Freiburg, Germany, have developed a method that speeds up healing, making wounds heal three times faster.

There is an old Swedish saying that one should never neglect a small wound or a friend in need. For most people, a small wound does not lead to any serious complications, but many common diagnoses make wound healing far more difficult. People with diabetes, spinal injuries, or poor blood circulation have impaired wound-healing ability. This means a greater risk of infection and chronic wounds—which can lead to serious consequences like amputation in the long run.

Now a group of researchers at Chalmers and the University of Freiburg have developed a method using electric stimulation to speed up the healing process. The study, "Bioelectronic microfluidic wound healing: a platform for investigating direct current stimulation of injured cell collectives," was published in the Lab on a Chip journal.

"Chronic wounds are a huge societal problem that we don't hear much about. Our discovery of a method that may heal wounds up to three times faster can be a game changer for diabetic and elderly people, among others, who often suffer greatly from wounds that won't heal," says Maria Asplund, Associate Professor of Bioelectronics at the Chalmers University of Technology and head of research on the project.

How electricity can heal wounds three times faster, The Chalmers University of Technology

The Biofire Smart Gun. Photographer: James Stukenberg for Bloomberg Businessweek

Topics: Biometrics, Biotechnology, Computer Science, Democracy, Materials Science, Semiconductor Technology

Tech Target (Alyssa Provazza, Editorial Director): "A smartphone is a cellular telephone with an integrated computer and other features not originally associated with telephones, such as an operating system, web browsing, and the ability to run software applications." Smartphones, however, have had a detrimental effect on humans regarding health, critical thinking, and cognitive skills, convenient though they are.

I've seen the idea of "smart guns" for decades. Like the fingerprint scan for biometric safes, it's a safeguard that some will opt for but most likely won't unless compelled by legislation, which in the current "thoughts and prayers" environment (i.e., sloganeering is easier than proposing a law if you continually get away with it), I'm not holding my breath. A recent, late 20th Century example:

In 1974, the federal government passed the National Maximum Speed Law, which restricted the maximum permissible vehicle speed limit to 55 miles per hour (mph) on all interstate roads in the United States.¹ The law was a response to the 1973 oil embargo, and its intent was to reduce fuel consumption. In the year after the National Maximum Speed Law was enacted, road fatalities declined 16.4%, from 54,052 in 1973 to 45,196 in 1974.²

In April of 1987, Congress passed the Surface Transportation and Uniform Relocation Assistance Act, which permitted states to raise the legal speed limit on rural interstates to 65 mph.³ Under this legislation, 41 states raised their posted speed limits to 65 mph on segments of rural interstates. On November 28, 1995, Congress passed the National Highway Designation Act, which officially removed all federal speed limit controls. Since 1995, all US states have raised their posted speed limits on rural interstates; many have also raised the posted speed limits on urban interstates and non interstate roads.

Conclusions. Reduced speed limits and improved enforcement with speed camera networks could immediately reduce speeds and save lives, in addition to reducing gas consumption, cutting emissions of air pollutants, saving valuable years of productivity, and reducing the cost of motor vehicle crashes.

Long-Term Effects of Repealing the National Maximum Speed Limit in the United States, Lee S. Friedman, Ph.D., corresponding author Donald Hedeker, Ph.D., and Elihu D. Richter, MD, MPH, National Library of Medicine, National Institutes of Health

Homo Sapiens, (Latin) "wise men," don't always do smart things.

In an office parking lot about halfway between Denver and Boulder, a former 50-foot-long shipping container has been converted into a cramped indoor shooting range. Paper targets with torsos printed on them hang from two parallel tracks, and a rubber trap waits at the back of the container to catch the spent bullets. Black acoustic foam padding on the walls softens the gunshot noise to make the experience more bearable for the shooter, while an air filtration system sucks particulates out of the air. It’s a far cry from the gleaming labs of the average James Bond movie, but Q might still be proud.

The weapons being tested at this site are smart guns: They can identify their registered users and won’t fire [for] anyone else. Smart guns have been a notoriously quixotic category for decades. The weapons carry the hope that an extra technological safeguard might prevent a wide range of gun-related accidents and deaths. But making a smart gun that’s good enough to be taken seriously has proved beyond difficult. It’s rare to find engineers with a strong understanding of both ballistics and biometrics whose products can be expected to work perfectly in life-or-death situations.

Some recent attempts have amounted to little more than a sensor or two slapped onto an existing weapon. More promising products have required too many steps and taken too much time to fire compared with the speed of a conventional handgun. What separates the Biofire Smart Gun here in the converted shipping container is that its ID systems, which scan fingerprints and faces, have been thoroughly melded into the firing mechanism. The battery-powered weapon has the sophistication of high-end consumer electronics, but it’s still a gun at its core.

A Smart Gun Is Finally Here, But Does Anyone Want It? Ashlee Vance, Bloomberg Business Week

Cancer cells are one of the main targets for expanded mRNA-LNP use. Credit: Iliescu Catalin / Alamy

Topics: Biology, Biotechnology, Cancer, COVID-19, Nanotechnology

Note: This is an advertisement on Nature Portfolio discussing that there may be a silver lining in the pandemic we've all experienced.

Lipid nanoparticles (LNPs) transport small molecules into the body. The most well-known LNP cargo is mRNA, the key constituent of some of the early vaccines against COVID-19. But that is just one application: LNPs can carry many different types of payload and have applications beyond vaccines.

Barbara Mui has been working on LNPs (and their predecessors, liposomes) since she was a Ph.D. student in Pieter Cullis’s group in the 1990s. “In those days, LNPs encapsulated anti-cancer drugs,” says Mui, who is currently a senior scientist at Acuitas. This company developed the LNPs used in the Pfizer-BioNTech mRNA vaccine against SARS-CoV-2. She says it soon became clear that LNPs worked even better as carriers of polynucleotides. “The first one that worked really well was encapsulating small RNAs,” Mui recalls.

But it was mRNA where LNPs proved most effective, primarily because LNPs are comprised of positively charged lipid nanoparticles that encapsulate negatively charged mRNA. Once in the body, LNPs enter cells via endocytosis into endosomes and are released into the cytoplasm. “Without the specially designed chemistry, the LNP and mRNA would be degraded in the endosome,” says Kathryn Whitehead, professor in the departments of chemical engineering and biomedical engineering at Carnegie Mellon University.

LNPs are an ideal delivery system for mRNA. “COVID accelerated the acceptance of LNPs, and people are more interested in them,” says Mui. LNP-mRNA vaccines for other infectious diseases, such as HIV or malaria, or for non-communicable diseases, such as cancer, could be next. And the potential doesn’t end with mRNA; there is even more scope to adapt LNPs to carry different types of cargo. But to realize these potential benefits, researchers first need to overcome challenges and decrease toxicity, increase their ability to escape from the endosomes, increase their thermostability, and work out how to effectively target LNPs to organs across the body.

Another potential application for LNPs is immunotherapy. Genetically modifying lymphocytes such as T cells or NK cells with chimeric antibody receptors (CARs) has proven useful in blood cancers. Often this process involves extracting lymphocytes from the blood of the person receiving the treatment, editing the cells in culture to express CARs, and then reintroducing them into the blood. However, LNPs could make it possible to express the desired CAR in vivo by shuttling CAR mRNA to the target lymphocytes. Mui has been involved in vivo studies showing this process works in mouse T cells (Rurik, J.G. et al. Science 375, 91-96, 2022). And Vita Golubovskaya, VP of research and development at ProMab Biotechnologies, presented preliminary data (available here) at the CAR-TCR Summit in September 2022 regarding LNPs that direct CAR-mRNA to NK cells, which can then kill target cells. “The RNA-LNP is a very exciting and novel technology that can be used for delivering CAR and bi-specific antibodies against cancer,” she says.

Beyond COVID vaccines: what’s next for lipid nanoparticles? Nature Portfolio

Credit: VTT Technical Research Centre of Finland

Topics: Biology, Biotechnology, Chemistry, Materials Science, Mechanical Engineering

A research group from VTT Technical Research Center of Finland has unlocked the secret behind the extraordinary mechanical properties and ultra-light weight of certain fungi. The complex architectural design of mushrooms could be mimicked and used to create new materials to replace plastics. The research results were published on February 22, 2023, in Science Advances.

VTT's research shows for the first time the complex structural, chemical, and mechanical features adapted throughout the course of evolution by Hoof mushroom (Fomes fomentarius). These features interplay synergistically to create a completely new class of high-performance materials.

Research findings can be used as a source of inspiration to grow from the bottom up the next generation of mechanically robust and lightweight, sustainable materials for various applications under laboratory conditions. These include impact-resistant implants, sports equipment, body armor, and exoskeletons for aircraft, electronics, or windshield surface coatings.

Mushrooms could help replace plastics in new high-performance ultra-light materials, VTT Technical Research Centre of Finland, Phys.org.

Image Credit: Down to the wire (IMAGE), Yale University

Topics: Biotechnology, Civilization, Climate Change, Nanotechnology

Accelerated climate change is a major and acute threat to life on Earth. Rising temperatures are caused by atmospheric methane, which is 30 times more potent than CO2 at trapping heat. Microbes are responsible for generating half of this methane. Elevated temperatures are also accelerating microbial growth and thus producing more greenhouse gases than can be used by plants, thus weakening the earth’s ability to function as a carbon sink and further raising the global temperature.

A potential solution to this vicious circle could be another kind of microbes that eats up to 80% of methane flux from ocean sediments that protect the Earth. How microbes serve as both the biggest producers and consumers of methane has remained a mystery because they are very difficult to study in the laboratory. In Nature Microbiology, surprising wire-like properties of a protein highly similar to the protein used by methane-eating microbes are reported by the Yale team led by Yangqi Gu and Nikhil Malvankar of Molecular Biophysics and Biochemistry at Microbial Sciences Institute.

The team had previously shown that this protein nanowire shows the highest conductivity known to date,  allowing the generation of the highest electric power by any bacteria. But to date, no one has discovered how bacteria make them and why they show such extremely high conductivity.

An ultra-stable protein nanowire made by bacteria provides clues to combating climate change, Yale University.

Image Source: MedPage Today

Topics: Biology, Biotechnology, Civilization, COVID-19, DNA, Epidemiology

Currently authorized bivalent COVID-19 boosters demonstrated similar protection against symptomatic illness from the XBB/XBB.1.5 Omicron subvariants as from BA.5-related subvariants, according to a CDC study.

From December 2022 to January 2023, the bivalent boosters' vaccine effectiveness (VE) against symptomatic infection was a similar 48% versus XBB/XBB.1.5-related strains and 52% versus BA.5-related sublineages, reported Ruth Link-Gelles, Ph.D., of the CDC's National Center for Immunization and Respiratory Diseases, and colleagues in Morbidity and Mortality Weekly Report (MMWR).

Meanwhile, Pfizer's updated booster demonstrated superior neutralizing antibody activity compared with the company's original product against all the latest Omicron subvariants, including XBB.1, according to Kena Swanson, Ph.D., of Pfizer Vaccine Research and Development in Pearl River, New York and colleagues, writing in the New England Journal of Medicine. Their findings contradict earlier research from other labs that found no significant difference in neutralizing activity with the bivalent over the monovalent vaccine.

According to the latest estimates from the CDC, XBB.1.5 is responsible for 49.1% of new COVID-19 cases in the U.S., while XBB is responsible for another 3.3%.

CDC: Bivalent COVID Vaccines Stop Illness From XBB.1.5

— And Pfizer lab data show better neutralization against the latest variants with the bivalent shot, Ingrid Hein, Staff Writer, MedPage Today

Some fireflies have a mystifying gift for flashing their abdomens in sync. New observations are overturning long-accepted explanations for how the synchronization occurs, at least for some species.

Topics: Biology, Biomimetics, Biotechnology, Computer Modeling, Mathematics

In Japanese folk traditions, they symbolize departing souls or silent, ardent love. Some Indigenous cultures in the Peruvian Andes view them as the eyes of ghosts. And across various Western cultures, fireflies, glow-worms, and other bioluminescent beetles have been linked to a dazzling and at times contradictory array of metaphoric associations: “childhood, crop, doom, elves, fear, habitat change, idyll, love, luck, mortality, prostitution, solstice, stars and fleetingness of words and cognition,” as one 2016 review noted.

Physicists revere fireflies for reasons that might seem every bit as mystical: Of the roughly 2,200 species scattered around the world, a handful has the documented ability to flash in synchrony. In Malaysia and Thailand, firefly-studded mangrove trees can blink on the beat as if strung up with Christmas lights; every summer in Appalachia, waves of eerie concordance ripple across fields and forests. The fireflies’ light shows lure mates and crowds of human sightseers, but they have also helped spark some of the most fundamental attempts to explain synchronization, the alchemy by which elaborate coordination emerges from even very simple individual parts.

Orit Peleg remembers when she first encountered the mystery of synchronous fireflies as an undergraduate studying physics and computer science. The fireflies were presented as an example of how simple systems achieve synchrony in Nonlinear Dynamics and Chaos, a textbook by the mathematician Steven Strogatz that her class was using. Peleg had never even seen a firefly, as they are uncommon in Israel, where she grew up.

“It’s just so beautiful that it somehow stuck in my head for many, many years,” she said. But by the time Peleg began her own lab, applying computational approaches to biology at the University of Colorado and at the Santa Fe Institute, she had learned that although fireflies had inspired a lot of math, quantitative data describing what the insects were actually doing was scant.

How Do Fireflies Flash in Sync? Studies Suggest a New Answer. Joshua Sokol, Quanta Magazine

Credit: Tom Mannion

Topics: Additive Manufacturing, Biology, Biotechnology, Environment, Genetics, Nanotechnology

For Hermes, the Greek god of speed, these bacterial sneakers would have been just the ticket. Modern Synthesis co-founders Jen Keane, CEO, and Ben Reeve, CTO, are now setting out to make them available to mere mortals, raising a $4.1 million investment to scale up production. Keane, a graduate from Central Saint Martins School of Art and Design in London, and synthetic biologist Reeve, then at Imperial College London, set up Modern Synthesis in 2020 to pursue ‘microbial weaving’.

Their goal is to produce a new class of material, a hybrid/composite that will replace animal- and petrochemical-made sneakers with a biodegradable, yet durable, alternative. The shoe's upper is made by bacteria that naturally produce nanocellulose—Komagataeibacter rhaeticus—and can be further genetically engineered to also self-dye by producing melanin for color.

The process begins with a two-dimensional yarn scaffold shaped by robotics, which the scientists submerge in a fermentation medium containing the cellulose-producing bacteria. The K. rhaeticus ‘weave’ the sneaker upper by depositing the biomaterial on the scaffold. Once the sheets emerge from their microbial baths, they are shaped on shoe lasts following traditional footwear techniques. “It’s more than the sum of its parts,” Reeves says of the biocomposite. “Initially the scaffold helps the bacteria grow, then the microbial yarn reinforces the material: it holds the scaffold together.” Once the shoe is made, it is sterilized and the bacteria are washed out.

Cellulose shoes made by bacteria, Lisa Melton, Nature Biotechnology

1 Soap, shampoo, and worm-like micelles Soaps and shampoos are made from amphiphilic molecules with water-loving (red) and water-hating (blue) parts that arrange themselves to form long tubes known as “worm-like micelles”. Entanglements between the tubes give these materials their pleasant, sticky feel. b The micelles can, however, disentangle themselves, just as entangled long-chain polymer molecules can slide apart too. In polymers, this process can be modeled by imagining the molecule sliding, like a snake, out of an imaginary tube formed by the surrounding spatial constraints. c Worm-like micelles can also morph their architecture by performing reconnections (left), breakages (down), and fusions (right). These operations occur randomly along the backbone, are in thermal equilibrium, and are reversible. (Courtesy: Davide Michieletto)

Topics: Biology, Biotechnology, DNA, Molecules

DNA molecules are not fixed objects – they are constantly getting broken up and glued back together to adopt new shapes. Davide Michieletto explains how this process can be harnessed to create a new generation of “topologically active” materials.

Call me naive, but until a few years ago I had never realized you can actually buy DNA. As a physicist, I’d been familiar with DNA as the “molecule of life” – something that carries genetic information and allows complex organisms, such as you and me, to be created. But I was surprised to find that biotech firms purify DNA from viruses and will ship concentrated solutions in the post. In fact, you can just go online and order DNA, which is exactly what I did. Only there was another surprise in store.

When the DNA solution arrived at my lab in Edinburgh, it came in a tube with about half a milligram of DNA per centimeter cube of water. Keen to experiment with it, I tried to pipette some of the solutions out, but they didn’t run freely into my plastic tube. Instead, it was all gloopy and resisted the suction of my pipette. I rushed over to a colleague in my lab, eagerly announcing my amazing “discovery”. They just looked at me like I was an idiot. Of course, solutions of DNA are gloopy.

I should have known better. It’s easy to idealize DNA as some kind of magic material, but it’s essentially just a long-chain double-helical polymer consisting of four different types of monomers – the nucleotides A, T, C, and G, which stack together into base pairs. And like all polymers at high concentrations, the DNA chains can get entangled. In fact, they get so tied up that a single human cell can have up to 2 m of DNA crammed into an object just 10 μm in size. Scaled up, it’s like storing 20 km of hair-thin wire in a box no bigger than your mobile phone.

Make or break: building soft materials with DNA, Davide Michieletto is a Royal Society university research fellow in the School of Physics and Astronomy, University of Edinburgh, UK

NIST researcher Megan Cleveland uses a PCR machine to amplify DNA sequences by copying them numerous times through a series of chemical reactions.
Credit: M. Cleveland/NIST

Topics: Biology, Biotechnology, COVID-19, Diversity in Science, NIST, Research, Women in Science

Scientists track and monitor the circulation of SARS-CoV-2, the virus that causes COVID-19, using methods based on a laboratory technique called polymerase chain reaction (PCR). Also used as the “gold standard” test to diagnose COVID-19 in individuals, PCR amplifies pieces of DNA by copying them numerous times through a series of chemical reactions. The number of cycles it takes to amplify DNA sequences of interest so that they are detectable by the PCR machine, known as the cycle threshold (Ct), is what researchers and medical professionals look at to detect the virus.

However, not all labs get the same Ct values (sometimes also called “Cq” values). In efforts to make the results more comparable between labs, the National Institute of Standards and Technology (NIST) contributed to a multiorganizational study that looked at anchoring these Ct values to a reference sample with known amounts of the virus.

Researchers published their findings in the journal PLOS One.

SARS-CoV-2 is an RNA virus: Its genetic material is single-stranded instead of double-stranded like DNA and contains some different molecular building blocks, namely uracil in place of thymine. But the PCR test only works with DNA, and labs first must convert the RNA to DNA to screen for COVID-19. For the test, RNA is isolated from a patient’s sample and combined with other ingredients, including short DNA sequences are known as primers, to transform the RNA into DNA.

RNA Reference Materials Are Useful for Standardizing COVID-19 Tests, Study Shows, NIST

Visual Abstract

Topics: Biology, Biotechnology, COVID-19, Research

To advance a novel concept of debulking virus in the oral cavity, the primary site of viral replication, virus-trapping proteins CTB-ACE2 were expressed in chloroplasts and clinical-grade plant material was developed to meet FDA requirements. Chewing gum (2 g) containing plant cells expressed CTB-ACE2 up to 17.2 mg ACE2/g dry weight (11.7% leaf protein), have physical characteristics and taste/flavor like conventional gums, and no protein was lost during gum compression. CTB-ACE2 gum efficiently (>95%) inhibited entry of lentivirus spike or VSV-spike pseudovirus into Vero/CHO cells when quantified by luciferase or red fluorescence. Incubation of CTB-ACE2 microparticles reduced SARS-CoV-2 virus count in COVID-19 swab/saliva samples by >95% when evaluated by microbubbles (femtomolar concentration) or qPCR, demonstrating both virus trapping and blocking of cellular entry. COVID-19 saliva samples showed low or undetectable ACE2 activity when compared with healthy individuals (2,582 versus 50,126 ΔRFU; 27 versus 225 enzyme units), confirming greater susceptibility of infected patients for viral entry. CTB-ACE2 activity was completely inhibited by pre-incubation with SARS-CoV-2 receptor-binding domain, offering an explanation for reduced saliva ACE2 activity among COVID-19 patients. Chewing gum with virus-trapping proteins offers a generally affordable strategy to protect patients from most oral virus re-infections through debulking or minimizing transmission to others.

Debulking SARS-CoV-2 in saliva using angiotensin-converting enzyme 2 in chewing gum to decrease oral virus transmission and infection, Molecular Therapy: Cell.com

Henry Daniell, Smruti K. Nair, Nardana Esmaeili, Geetanjali Wakade, Naila Shahid, Prem Kumar Ganesan, Md Reyazul Islam, Ariel Shepley-McTaggart, Sheng Feng, Ebony N. Gary, Ali R. Ali, Manunya Nuth, Selene Nunez Cruz, Jevon Graham-Wooten, Stephen J. Streatfield, Ruben Montoya-Lopez, Paul Kaznica, Margaret Mawson, Brian J. Green, Robert Ricciardi, Michael Milone, Ronald N. Harty, Ping Wang, David B. Weiner, Kenneth B. Margulies, Ronald G. Collman

Hybrid device: A diagram of the layers in the new soft pressure sensor. (Courtesy: the University of Texas at Austin)

Topics: Applied Physics, Biotechnology, Nanotechnology

Wearable pressure sensors are commonly used in medicine to track vital signs, and in robotics to help mechanical fingers handle delicate objects. Conventional soft capacitive pressure sensors only work at pressures below 3 kPa, however, meaning that something as simple as tight-fitting clothing can hinder their performance. A team of researchers at the University of Texas has now made a hybrid sensor that remains highly sensitive over a much wider range of pressures. The new device could find use in robotics and biomedicine.

The most common types of pressure sensors rely on piezoresistive, piezoelectric, capacitive, and/or optical mechanisms to operate. When such devices are compressed, their electrical resistance, voltage, capacitance, or light transmittance (respectively) changes in a well-characterized way that can be translated into a pressure reading.

The high sensitivity and long-term stability of capacitive pressure sensors make them one of the most popular types, and they are often incorporated into soft, flexible sensors that can be wrapped around curved surfaces. Such sensors are popular in fields such as prosthetics, robotics, and biometrics, where they are used to calibrate the strength of a robot’s grip, monitor pulse rates, and blood pressure, and measure footstep pressure. However, these different applications involve a relatively wide range of pressures: below 1 kPa for robotic electronic skin (e-skin) and pulse monitoring; between 1 and 10 kPa for manipulating objects; and more than 10 kPa for blood pressure and footstep pressure.

Wearable pressure sensors extend their range, Isabelle Dumé, Physics World

Magnetic prosthetic: A magnetic sensing array enables a new tissue tracking strategy that could offer advanced motion control in artificial limbs. (Courtesy: MIT Media Lab/Cameron Taylor/Vessel Studios)

Topics: Biotechnology, Magnetism, Materials Science, Medicine, Nanotechnology, Robotics

Cultural reference: The Six Million Dollar Man, NBC

In recent years, health and fitness wearables have gained popularity as platforms to wirelessly track daily physical activities, by counting steps, for example, or recording heartbeats directly from the wrist. To achieve this, inertial sensors in contact with the skin capture the relevant motion and physiological signals originating from the body.

As wearable technology evolves, researchers strive to understand not just how to track the body’s dynamic signals, but also how to simulate them to control artificial limbs. This new level of motion control requires a detailed understanding of what is happening beneath the skin, specifically, the motion of the muscles.

Skeletal muscles are responsible for almost all movement of the human body. When muscle fibers contract, the exerted forces travel through the tendons, pull the bones, and ultimately produce motion. To track and use these muscle contractions in real-time and with high signal quality, engineers at the Massachusetts Institute of Technology (MIT) employed low-frequency magnetic fields – which pass undisturbed through body tissues – to provide accurate and real-time transcutaneous sensing of muscle motion. They describe their technique in Science Robotics.

Magnetic beads inside the body could improve control of bionic limbs, Raudel Avila is a student contributor to Physics World

A computer simulation of the structure of the coronavirus SARS-CoV-2.Credit: Janet Iwasa, University of Utah

Topics: Biology, Biotechnology, COVID-19, DNA, Existentialism, Research

The coronavirus sports a luxurious sugar coat. “It’s striking,” thought Rommie Amaro, staring at her computer simulation of one of the trademark spike proteins of SARS-CoV-2, which stick out from the virus’s surface. It was swathed in sugar molecules, known as glycans.

“When you see it with all the glycans, it’s almost unrecognizable,” says Amaro, a computational biophysical chemist at the University of California, San Diego.

Many viruses have glycans covering their outer proteins, camouflaging them from the human immune system like a wolf in sheep’s clothing. But last year, Amaro’s laboratory group and collaborators created the most detailed visualization yet of this coat, based on structural and genetic data and rendered atom-by-atom by a supercomputer. On 22 March 2020, she posted the simulation to Twitter. Within an hour, one researcher asked in a comment: what was the naked, uncoated loop sticking out of the top of the protein?

Amaro had no idea. But ten minutes later, structural biologist Jason McLellan at the University of Texas at Austin chimed in: the uncoated loop was a receptor-binding domain (RBD), one of three sections of the spike that bind to receptors on human cells (see ‘A hidden spike’).

Source: Structural image from Lorenzo Casalino, Univ. California, San Diego (Ref. 1); Graphic: Nik Spencer/Nature

How the coronavirus infects cells — and why Delta is so dangerous, Megan Scudellari, Nature

A robotic hand with the AiFoam artificially innervated smart foam, which enables it to sense objects in proximity by detecting their electrical fields and also self-heals if it gets cut, is pictured at National University Singapore's Materials Sciences and Engineering lab in Singapore June 30, 2021. REUTERS/Travis Teo

Topics: Biology, Biotechnology, Materials Science, Polymer Science, Robotics

SINGAPORE, July 6 (Reuters) - Singapore researchers have developed a smart foam material that allows robots to sense nearby objects, and repairs itself when damaged, just like human skin.

Artificially innervated foam, or AiFoam, is a highly elastic polymer created by mixing fluoropolymer with a compound that lowers surface tension.

This allows the spongy material to fuse easily into one piece when cut, according to researchers at the National University of Singapore.

"There are many applications for such a material, especially in robotics and prosthetic devices, where robots need to be a lot more intelligent when working around humans," explained lead researcher Benjamin Tee.

To replicate the human sense of touch, the researchers infused the material with microscopic metal particles and added tiny electrodes underneath the surface of the foam.

Smart foam material gives robotic hand the ability to self-repair, Travis Teo, Lee Ying Shan, Reuters Science

Artist’s impression of UQ’s new quantum microscope in action. Credit: The University of Queensland

Topics: Biology, Biotechnology, Instrumentation, Quantum Mechanics, Quantum Optics

In a major scientific leap, University of Queensland researchers have created a quantum microscope that can reveal biological structures that would otherwise be impossible to see.

This paves the way for applications in biotechnology, and could extend far beyond this into areas ranging from navigation to medical imaging.

The microscope is powered by the science of quantum entanglement, an effect Einstein described as “spooky interactions at a distance.”

Professor Warwick Bowen, from UQ’s Quantum Optics Lab and the ARC Centre of Excellence for Engineered Quantum Systems (EQUS), said it was the first entanglement-based sensor with performance beyond the best possible existing technology.

“This breakthrough will spark all sorts of new technologies — from better navigation systems to better MRI machines, you name it,” Professor Bowen said.

“Entanglement is thought to lie at the heart of a quantum revolution. We’ve finally demonstrated that sensors that use it can supersede existing, non-quantum technology.

“This is exciting — it’s the first proof of the paradigm-changing potential of entanglement for sensing.”

Major Scientific Leap: Quantum Microscope Created That Can See the Impossible, University of Queensland

MS TECH / SOURCE PHOTO: GETTY

Topics: Biology, Biotechnology, Civics, Ethics, Existentialism

The DNA database used to find the Golden State Killer is a national security leak waiting to happen
Antonio Regalado, Technology Review